1. Field of the Invention
The present invention relates to an emitting pipe, and more particularly to an emitting pipe boring method capable of easily and accurately punching an ejection hole of a tube on a discharging portion of a pressure reducing drip regardless of a variation in a distance between pressure reducing drips and an emitting pipe with a hole formed by the same.
2. Description of the Related Art
As known well, an emitting pipe has a number of ejection holes formed on a drip pressure reducing hose such that water flowing in the drip pressure reducing hose can be ejected through the ejection holes. As shown in FIG. 8, a number of pressure reducing drips 2 are attached to the inside of the drip pressure reducing hose at specified intervals. The pressure of water flowing in a drip pressure reducing hose 1 is reduced by the pressure reducing drips 2 such that the pressure of water flowing in leading and rear portions of the drip pressure reducing hose is made to be uniform.
As shown in FIG. 9, each of the pressure reducing drips 2 includes an introducing portion 21 for introducing water into the drip, a pressure reducing portion 22 for reducing the pressure of the introduced water, and a discharging portion 23 for discharging the water with a reduced pressure to the outside. The discharging portion 23 is positioned below an ejection hole 11 of the drip pressure reducing hose 1.
The emitting pipe is generally manufactured by an apparatus shown in FIG. 10. The apparatus for manufacturing an emitting pipe includes a drip pressure reducing hose molding unit 3 which has a sizing portion 3a for melting resin to form the drip pressure reducing hose 1; a drip supply unit 4 which supplies drips toward the drip pressure reducing hose molding unit 3; a cooling unit 5 which cools the drip pressure reducing hose 1 that is molded by the drip pressure reducing hose molding unit 3 by passing it through water; a first drawing portion 6 and a second drawing portion 6a which draw an end of the drip pressure reducing hose 1 that has passed through the cooling unit 5 at a specified velocity; and a boring unit 7 which is disposed between the first drawing portion 6 and the second drawing portion 6a to bore an ejection hole on the drip pressure reducing hose 1.
Further, the boring unit 7 includes a rail 71 which supports a lower portion of the drip pressure reducing hose 1 moving as shown in FIG. 11, and a rotation punch 72 which is installed on the upper side of the rail 71 to rotate at a specified velocity by a driving motor 72a and is mounted with a number of punches 72b disposed on the outside of the rotation punch 72 at equal intervals.
Further, the rotation punch 72 is operated according to detection signals transmitted from a drip projection detecting unit 8 positioned at the front side in a moving direction of the drip pressure reducing hose. For this operation, a circumferential distance L1 between the punches 72b mounted on the rotation punch 72 at equal intervals is formed relatively larger than a distance L2 between positions of the drip projection detecting unit 8 and the rotation punch 72. Reference numerals 60 and 60a denote upper and lower drawing rolls.
However, in the conventional emitting pipe boring apparatus, a circumferential distance between the punches, a distance between the drip projection detecting unit and the rotation punch and a moving velocity of the drip pressure reducing hose should be accurately set in order to bore an ejection hole at an accurate position of the drip pressure reducing hose, that is, a position of the discharging portion of the drip. Accordingly, trouble and inconvenience due to difficulty in the operation cause inefficiency of the operation, a material loss due to a high defect ratio, and a reduction of economical efficiency.